Re: Zoomable Number Line

Hi MIF

Did you mean?:

Zac Brown Band Knee Deep

"Gonna put the the world away for a minutePretend I don't live in itSunshine gonna wash my blues away...................Wishing I was knee deep in the water somewhereGot the blue sky breeze ...........................................Never been so happy Never felt so highAnd I think I might have found me my own kind of paradise"

But my frogs preferred wallowing in the mud at the bottom of the old pond.

Bob

Children are not defined by school ...........The FonzYou cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Re: Zoomable Number Line

(More may follow when my creativity level has recovered. Spent too long on an unprovable identity!)

Copied then added to what is there. Whoops. I've lost all the formatting.

What is this all about?

See that numbers behave the same, whether they are 1,2,3, or 10,20,30, or 0.01,0.02,0.03, etc...

It is a great way to learn about decimals: Zoom in and look at: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, ... Then ask: what is 0.9 + 0.1 ?

Do the same after zooming in further: What is 0.09 + 0.01? What is 0.19 + 0.01? What is 0.99 + 0.01?

MY SUGGESTIONS

You can track left and right along the line by clicking on one of the arrows. You will track faster if you move outwards along the arrow. Try this. At the start you will see the counting numbers wizz past. Stop when you reach 100. Go back to zero. Zoom in to show 0.1, 0.2, 0.3, ......... Now try tracking right. The tenths wizz by. How long does it take to reach 100 now? Try zooming in to 0.01, 0.02, 0.03, ...... How long does it take to track across to 100 now?Test yourselfStart at 0. Use the zoom and tracking to find these numbers 3.4 17.85 -17.85 100.00357

COMMENT. If a learner can do these he / she has a pretty good understanding of the way the decimals behave, I think.

Bob

Children are not defined by school ...........The FonzYou cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Re: Zoomable Number Line

Re: Zoomable Number Line

hi gyanshrestha

If you are a competent arithmetician, then I can understand why you might wonder. I have taught children for 38 years and have frequently found some who do not have a good grasp of how the decimal number system works.

This interactive resource shows that it is possible to subdivide each interval into 10 parts so learners can begin to understand tenths hundredths etc ... 0.1, 0.01, 0.001 and so on. They can see how decimal place values work and get a feel for 'infinite' sub-divisibility.

The text in the posts above show some of the applications:

eg. what comes next after 0.7, 0.8, 0.9 ....? And of course you can ask this question at any level.

eg. Finding a number on the line. I used the example of 100.00357. First the learner has to track to 100. They might do this the slow way by counting up in ones, but how much better to realise that you can zoom out a level and go up in tens. Then you have to zoom in and in and in so that you are at 100.00 Understanding that needs to be done is a crucial learning step. And, being interactive, the learner can immediately see if they have gone off track. Then they must zoom in and track to find the next digits. You just cannot do that on a whiteboard or on paper!

I am working in a primary school ( aged 4 to 11) for the next few days so I am going to encourage the teachers to give it a try. I think they will find new uses that I haven't thought of yet.

Here's a more advanced challenge for you. If each 'track one scale unit' costs a single key press and similarly, each 'zoom up or down a level'; then what is the least number of key presses to go from the start position to 100.00357 ?

(Note: I don't know the answer yet. One of the great things about superior teaching resources is that you can set questions to which you don't know the answer but are nevertheless confident there is one.)

Bob

Children are not defined by school ...........The FonzYou cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Re: Zoomable Number Line

hi MIF

i think that there should be zoom in and zoom out buttons.a feature that would be very helpful is being able to draw intervals to find their intersection,but i'm not sure how doable that is...

Here lies the reader who will never open this book. He is forever dead.Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and PunishmentThe knowledge of some things as a function of age is a delta function.

Re: Zoomable Number Line

hi MIF

yes that is very practical especially for students that have a focus on algebra.

another thing.sometimes when i zoom in i go to far to the left and when i press the zero button it centers it but it also resets the zoom. it would be nice to have separate buttons for centering the number line at 0 and for resetting the zoom.

one more idea.you could add a place to type in a number and it finds it instantly(well,maybe not instantly) on the line,so that e.g. i don't have to have my arm fall off just to reach 154.7

Here lies the reader who will never open this book. He is forever dead.Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and PunishmentThe knowledge of some things as a function of age is a delta function.

Re: Zoomable Number Line

hi bob

i don't mind the arm that much anyway!

Here lies the reader who will never open this book. He is forever dead.Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and PunishmentThe knowledge of some things as a function of age is a delta function.